From: Alan Friedman <alan@greatarrow.com>
Date: February 11, 2006 2:00:15 PM MST
To: Astro_IIDC@yahoogroups.com
Subject: Re: [Astro_IIDC] Re: Saturn at Opposition
Hi Duane -
Thanks! Did he post the link to APOD? It has gotten quite a bit of play recently on NASA science news and Spaceweather too. It's a nice image but I think the lunar/Italian alp connection was a good hook.
I was excited to have the Plato/Alpes image chosen for APOD - they don't use much earthbound lunar/planetary stuff.
This image was made from 20 streams of data captured on August 25th (hasn't been much opportunity to see the moon here over the last few months) - I finished processing the mosaic during the last couple of weeks. I posted a link to the image here in a previous post, I think.
What is the Macastronomer group - I don't know that one?
best,
Alan
On Feb 11, 2006, at 3:48 PM, Duane wrote:
Alan, your lunar shots on nasa's site are spectacular. David Illig just posted links to it in
macastronomer group.
Is that an older shot or a recent one?
Duane
--- In Astro_IIDC@yahoogroups.com, Alan Friedman <alan@...> wrote:
>
> Hi Duane -
>
> I believe Milton posted a link to Wes' web index in an earlier post. He
> is an active participant in the Astromart Planetary Imaging forum
> (which is a great forum for this topic, BTW). His lunar work with an
> 18" Starmaster is the best I've seen from this planet.
>
> I thought I would copy a post I made earlier today on the Astro-Physics
> forum. Seeing is huge, no doubt - but be sure to have a look at
> Damian's mars images from the UK in average - good seeing. There is
> hope short of lugging all your stuff down south!
>
> I hope to have a website live by the end of this month - thanks for
> asking.
>
> cheers-
> Alan
>
> ps - the whiner I refer to in my post below is me, not you! 8^)
>
> -----------------------------
>
> Hi Milt -
>
> I think your comments are a good summary. In planetary imaging, seeing
> is still a
> critical factor - but it factors differently than in visual because you
> can pick the
> image apart into 33ms bits, choose the good ones and eliminate the bad
> ones. In
> this way, the seeing is not a monolithic experience. In virtually every
> stream there
> are images typical of 6/10 seeing and 3/10 seeing - the question is how
> many are
> of the 6/10 variety in a period of time before features move and can no
> longer be
> averaged to reduce noise. The Pickering scale as we use it for visual
> observing
> does not really work well to describe limits for planetary imaging (I
> wonder how
> many imagers begin and end their sessions with a star test - poor,
> fair, good, very
> good might be just as useful).
>
> While we often talk (and whine) about the seeing conditions it is
> important to
> remember that very good imaging results can be obtained in fair-good
> seeing (5
> -6/10). You need enough aperture for adequate light to record with a
> long focal
> length. Assuming good processing skills, in conditions where 600 frames
> at 6/10
> quality can be gleaned and averaged, the postion of the Encke division
> will be
> recorded over a good section of the ansae of saturn's rings.
>
> These conditions can drift in and out many times over a 30 minute
> observing
> session and can be found during some part of the night in almost any
> location. A
> big part of the challenge is getting out frequently enough to catch
> them. Damian's
> images are truly spectacular - also remember that he has been out to
> image mars
> more than 100 times during this apparition.
>
> steady skies!
> Alan
>
>
>
> ---------- Original Message ----------------------------------
> From: "wilcoxmilton" <wilcoxmilton@...>
> > I guess the difference must be that in imaging you get to stack so
> > many frames (hand picked?) that it effectively neutralizes the effects
> > of mediocre seeing? At the eyepiece, I find it extremely difficult to
> > mentally register the detail available in brief moments of clarity (I
> > know I am not in the skill class of many of the visual planetary
> > observers here).
>
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